Abstract: The disclosure teaches that a cyclable program loop can be alternatively used to selectively initiate subprograms or as a timing signal generator, the latter preferably in a maintenance mode of a machine in which the loop resides. A programmable machine has a cyclable program loop with a preset number of program steps. First sequences of internal machine operations cooperate with said loop such that, based upon detection of predetermined status signals, one of a plurality of object programs may be initiated. In a second mode of operation, the status signals are suppressed; and the cyclable program loop is selectively used in a second mode or as in said first mode. In a preferred form, the second mode, the cyclable program loop, is a timing cycle usable in connection with maintenance procedures on the programmable machine. At the expiration of each timing cycle, the loop supplies a reference signal for operating a second set of internal machine functions.